Wet Bath Conversion

I know that most people covet a dry bath, but we have had a dry bath for the
last 23 years and can say that with the limited size of the GMC it is not a very
good option for big people. I am 6'5" and my wife is 5' 10" and we found
that the dry bath in the Royale was just too small for comfort and that the shower
was so small that it rarely got used. In fact I would guess that in the 23
years of ownership of this GMC it was not used a dozen times. We either stayed
in campgrounds with showers every other day or so, or visited our friends with
big SOBs and begged a shower from them: though after several days without a
shower begging was not necessary, they provide the shower in self defense.

The following image shows the original bath.

After looking at the options it appeared that the space used by the shower
could better be used in making the bath larger and adding some badly needed
storage to the kitchen. Thus started a fairly major remodel of the GMC
interior.

The first step was to strip out the interior from the cockpit back to the
closets except for the kitchen and re-insulate, put in a new headliner and new
wall panels. The following picture shows the bath area after the shower
and bathroom cabinet are removed but with the toilet still in position with the
fixture to raise it several inches. Even the tile floor that was installed
last year will have to go. It was amazing how little storage was in the
original cabinets after the original manufacturer installed the duct work and
plumbing, They just did not seem to know how critical good clean storage is in a
vehicle this size.

The design for the bath was somewhat dictated by our accidental acquisition
of a bath counter top while visiting Northwest RV Supply in Eugene Oregon. They
sell surplus RV supplies they have gotten from major RV manufacturers in the
area. This was a L shaped solid surface counter with sink at a cost of $100.

Using the computer to create initial drawings of a new layout and then
cardboard to build several mockups we came up with a design that we thought
would work. The resulting design used about half of the original shower in
the new bath and left the rest for use as pantry pullout storage in the kitchen.
Had we known how much added storage we would be able to create with the kitchen
remodel that followed we would have used more of the space in the bath and made
the pantry pull outs smaller. The drawing blow shows the original configuration
in gray lines with the new configuration overlayed in black. The yellow
shows the storage areas allocated in the new bath.

The toilet location is not very flexible since it needs to be plumbed
directly into the black water tank so it ended up only 1.5 inches outboard from
its original location. The cabinet work ended up being totally different
with an incredible amount of storage for a small bath.

We also wanted to have shower possibility so opted for a wet bath design.

Some complications did appear. Due to our height we needed to keep the
floor of the bath at the level of the regular GMC floor. This did not
allow the shower to drain into either of the tanks with the required trap. To
solve this problem I chose to go with a marine industry solution and added a
shower drain pump to move the shower water to the holding tank. This has a
significant advantage of being able to now put the shower water into whichever
tank has the most room, and we have also provided for a direct dump to the
ground if we are in an appropriate location thus saving space in the holding
tanks.

The outside walls of the bath were insulated with additional foil back foam
board, with 1/2" on the upper walls and a full inch to 1.5 inches around the
wheel wells.

The cabinet work was built with 1/8" and 1/4" plywood with cedar framing to
keep weight to a minimum.

The shower drain location was dictated by the location of the black water tank,
the gas tank and frame. It ended up going through the floor between the
black water tank and a frame cross member. I had to be a little creative
with the plumbing underneath to connect up to the pump, but it all seems to
work.

A neat benefit of doing your own work is that it is possible to do things
like raise the toilet several inches to make it more comfortable for us of the aging
generation. We had already replaced the toilet with the regular style
Sea-Land china bowl unit and added a riser but still felt that additional height
would be more comfortable for us tall people so it is now even higher.

Here are some pictures of the bath after initial construction of cabinets.
note the amount of storage that can be had under the sink by just being careful
with the routing of ducts and plumbing.

To make this a wet bath I built a fiberglass pan in place and then
fiberglassed all the walls and cabinet work. For the pan I pre-sloped the
floor to the drain by troweling in a layer of resin mixed with micro balloons but
could have used almost anything from resin with sawdust to thin-set mortar.
After the floor was properly sloped at about 1/4" to the foot I then glassed
over it using fiberglass matt and cloth and polyester resin. This went up
the sides of the bath about 4 inches all the way around. This required
adding a 4" threshold where the door was located. Glass cloth and mat was
added until I had about a 1/4" layer. which will be strong enough to
stand up to any king of abuse.

For the upper portions of the bath and cabinets I first rounded all outside
corners and then filleted the inside corners with a mixture of epoxy and micro
balloons. Here the use of the micro balloons really helps since they
smooth very nicely and required very little sanding before proceeding. I
then put on a layer of 4 oz cloth with epoxy over all the walls being sure to
overlap all corners with two layers and let it overlap the fiberglass pan on the
bottom so there would be no joints to leak. By using a minimal amount of
resin (just enough to wet out the cloth there is very little sanding to be done.
If a second coat of resin is put on as soon as the first coat gels then no
sanding is required between coats. If you are careful only minimal sanding
is required after the second coat and then mostly at the seams. I used epoxy for
the walls mostly because there are a lot less fumes, but even then I used a
respirator for all the work and an exhaust fan to remove any fumes.

I then sanded the interior and painted with a two part off white epoxy which
I had on hand, otherwise I would have used a mono-epoxy or urethane enamel.

The cabinet doors were built out of 1/2 inch Baltic birch plywood and painted
with 2 coats of primer then sanded and painted with the epoxy. This gave
almost a glass like finish.

Since this is a wet bath much thought went into how to seal the doors.
I came up with many schemes, most of which required fancy door configurations or
special work around the door openings or expensive moldings or seals. One
day while at Home Depot I was looking at weather stripping and found a cheap
stick on weather seal that works great. I used touch latches behind each
of the doors to hold them closed so the doors are smooth and clean looking.

The L shaped counter top from the salvage yard was then cut and modified and
placed on the cabinet and sealed around the edges where it meets the walls.

The faucets were pretty much standard Delta products from Home Depot.
For the shower we are using a sink sprayer on a long flexible hose which tends
to keep water usage to a minimum.

The floor pan was tiled with 2x2 porcelain tiles from "Daltile" which are
very thin and therefore very light.

The following pictures show the bath after completion. Note the amount
of storage, including a large cloths hamper which has a net bag the hangs inside
and opens when the door is opened.

A shower curtain is used to cover the entry door while taking a shower.

Since finishing this bath and spending 6 weeks in the Arizona desert this
winter we used the shower in the wet bath format many more times than in the previous
23 years of motorhoming with the separate shower stall.